In June 2018 a military-diplomatic source told TASS that Russia's defense companies are working to complete S-400 deliveries to Turkey in May 2019

WASHINGTON, March 9. /TASS/. The process of delivering Russia's S-400 missile defense systems to Turkey goes very smoothly, director for international cooperation and regional policy at Russia's Rostec defense and technology company Viktor Kladov told Defense News in an interview published on Friday.

"This is a system that the Turkish government wants, and we want to give it. And so far it is going very smoothly," Kladov said.

"We are cooperating with partners and potential partners, regardless of who likes it and who doesn't like it," he added. "It's business. It's just business ties," he stressed.

"A Russian journalist asked me: 'If the Americans don’t give the F-35 to Turkey, does it mean you will provide the Su-35?' And I said: 'No, it doesn’t work that way.' In the first place, it will be decided by the Turkish," Kladov said.

In November 2016 reports said that Turkey will purchase Russia's S-400 missile defense systems. In September 2017 Russia confirmed that a contract was signed with Turkey on S-400 delivery. In June 2018 a military-diplomatic source told TASS that Russia's defense companies are working to complete S-400 deliveries to Turkey in May 2019.